Microorganisms In Water Samples Research Articles

Polyethersulfone (PES) Filters Improve the Recovery of Legionella spp. and Enhance Selectivity against Interfering Microorganisms in Water Samples.

In the analysis of water samples, the type of filtration membrane material can influence the recovery of Legionella species, although this issue has been poorly investigated. Filtration membranes (0.45 µm) from different materials and manufacturers (numbered as 1, 2, 3, 4, and 5) were compared: mixed cellulose esters (MCEs), nitrocellulose (NC), and polyethersulfone (PES). After membrane filtration of samples, filters were placed directly onto GVPC agar and incubated at 36 ± 2 °C. The highest mean counts of colony-forming units and colony sizes for Legionella pneumophila and Legionella anisa were obtained with PES filters (p < 0.001). All membranes placed on GVPC agar totally inhibited Escherichia coli and Enterococcus faecalis ATCC 19443 and ATCC 29212, whereas only the PES filter from manufacturer 3 (3-PES) totally inhibited Pseudomonas aeruginosa. PES membrane performance also differed according to the manufacturer, with 3-PES providing the best productivity and selectivity. In real water samples, 3-PES also produced a higher Legionella recovery and better inhibition of interfering microorganisms. These results support the use of PES membranes in methods where the filter is placed directly on the culture media and not only in procedures where membrane filtration is followed by a washing step (according to ISO 11731:2017).

Microbiological Assessment of Rainwater and Air Quality of Some Areas in Port Harcourt

The microbiological quality of Rainwater and air of the market, hospital, and residential area was evaluated. Roof-harvested and direct rainwater samples were collected from the three aforementioned locations. The air quality was investigated using the plate sedimentation method. Culture-based techniques were used for the enumeration and isolation of microorganisms in water samples, while the identities were confirmed using morphological, microscopic, and biochemical tests. The range of the total heterotrophic bacterial counts (THBC) of rainwater was 1.2±7.1x106 to 6.1±1.1 x106 cfu/ml, total coliform count (TCC) ranged between 8.0±0.00 x103 to 30.5 ±2.1 x103 cfu/ml, faecal coliform counts (FCC) ranged between 1.0±0.00×103 to 6.0±0.00×103 cfu/ml, fungal counts ranged from 2.0±0.00x103 to 11.0±0.00x103 cfu/ml. The THB, TCC, and FCC of the air samples, ranged between 0.04±0.02 to 0.13±0.04 cfu/min-m2, 0.01±0.00to 0.03±0.00 cfu/min-m2, and 0.01±0.00 to 0.02±0.00 cfu/min-m2, respectively. There was a significant difference (P≤ 0.05) in the total heterotrophic bacterial load of the roof-harvested rainwater and the direct rainwater of the residential area, roof-harvested and direct rainwater of the hospital. Statistically, there was a significant difference (P≤ 0.05) in the total coliform counts of the water with the coliform counts of the roof-harvested rainwater of the market being significantly higher than the coliform counts recorded in other locations. Seven bacterial genera belonging to Micrococcus sp, Staphylococcus, Escherichia coli, Proteus sp, Pseudomonas sp, Enterobacter sp, and Bacillus sp were isolated. The fungal isolates were Candida sp, Mucor sp, Rhizopus sp, Penicillium sp, Aspergillus niger, and Aspergillus flavus. The results showed that rainwater is not fit for consumption due to its components and can cause harm to individuals if consumed without treatment. proper treatment is recommended before consumption. The results also showed that the microbiological quality of the air samples was influenced by their environment.

Stable nitrogen isotopes in octocorals as an indicator of water quality decline from the northwestern region of Cuba.

Eutrophication is one of the causes of the degradation of reefs worldwide. The aim of this research is to determine if sewage discharge reaches the fore reefs at northwest of Cuba using δ15N in tissues of the octocorals Eunicea flexuosa and Plexaura kuekenthali and the concentration of microbiological and physical-chemical variables. Thirteen reefs at 10-m depth were selected near river basins and far from the urban and industrial development of Havana City. Branch tips of both species were collected, the concentrations of nutrient and microorganisms in water samples were quantified, and horizontal visibility in the water (Vis) was determined. Overall, δ15N of E. flexuosa ranged from 1.5 to 6.3‰ and P. kuekenthali from 1.7 to 6.7‰. The tissue of both species was significantly enriched in 15N in reefs near polluted watersheds compared with reefs far from pollution by anthropogenic activities. The δ15N of both species showed a positive and significant correlation with the concentration of fecal and total coliform bacteria, heterotrophic bacteria, and NH4+ and a negative and significant correlation with the Vis. The δ15N of the two species and microbiological and physical-chemical variables evidenced water quality decline by sewage discharge that reached reefs near polluted watersheds.

Heat-Transfer Method: A Thermal Analysis Technique for the Real-Time Monitoring of Staphylococcus aureus Growth in Buffered Solutions and Digestate Samples.

The identification and quantification of microorganisms in water samples are crucial to improve processes in organic waste treatment facilities. Most of the currently available tests are either labor intense or costly, and they do not allow determination of the dynamics within microbial communities in digestate samples. This study is the first report on the use of thermal analysis, specifically the heat transfer method (HTM), to monitor microbial load in aqueous systems and digestate samples. Staphylococcus aureus was used as a model organism, and different concentrations in water were measured by the HTM. It was demonstrated that there was a positive correlation between the thermal resistance and concentration of the bacterial cells. Subsequently, the influence of temperature on growth rates was studied and confirmed by plating experiments and scanning electron microscopy (SEM). These results showed the possibility to monitor the temperature-dependent growth of S. aureus using the HTM. To determine if this technique can be applied for studying complex matrices, digestate samples were collected from a number of sources and plated on nutrient agar plates. The bacterial cultures derived from single colonies were characterized and identified by sequencing of DNA regions for 16S rRNA. HTM measurements were performed in diluted or centrifuged digestate samples that were enriched with S. aureus. The results indicated that it is possible to evaluate microbial load even in samples containing other organic material. The thermal analysis method has the potential to provide a low-cost monitoring option, which is simple to use and provides real-time analysis, thus improving the existing monitoring procedures in organic waste treatment facilities.

EVALUATION OF THE EFFECTIVENESS OF TEST-SYSTEMS FOR RAPID IMPLEMENTATION OF SANITARY-BACTERIOLOGICAL ANALYSIS OF WATER

There was executed the assessment of the method of the detection and identification of sanitary-indicative microorganisms in water samples with the use of test systems IDEXX manufactured by IDEXX Laboratories, Inc (USA), based on the use of chromogenic culture media and reagents in accordance with the methodology developed by the manufacturer. IDEXX method was found not to be inferior to the reference methods of water analysis applied in Russia and in international practice. Comparative evaluation of crops showed the consistency of results, as in the study of contaminated water with natural microbiocenoses and water modeling of water bodies, contaminated by daily cultures test microganisms. The method allows reduce time of an analysis due to the exclusion of the biochemical reactions (oxidase activity, fermentation of carbohydrates, formation of indole, etc.) needed to determine species of microorganisms, and to obtain the final result of the analysis after 24 hours. On the basis of obtained results test systems IDEXX Laboratories (USA) may be applied on the territory of the Russian Federation for the assessment of water quality according to sanitary-microbiological indices

MICROALARM: “a new system for rapid quantification of the total bacteria in water samples”

Background Analytical methods applied in diagnostic microbiology laboratories are usually performed manually and have several drawbacks, the long time-to-results (48–72 h) being the major one. Rapid detection methods may overcome the disadvantages of traditional microbiological methods and achieve fast detection, which will help preventing the spread of waterborne pathogens and outbreaks of waterborne diseases. The objective of the MICROALARM project is to validate a platform for monitoring the quantification of the total bacteria present in water samples. Methods The MICROALARM system integrates a microfluidic cartridge where the microorganisms from the sample are labelled to facilitate the detection and measurement by a fluorescence sensor. The prototype system has been validated according to ISO 16140-2 : 2016 in the laboratory through the comparison with conventional (culture isolation) and alternative methods (flow cytometry) to determine whether the method is suitable for quantifying microorganisms in water samples. Results The system will be capable of processing, labelling and quantifying automatically the total bacteria of the water sample using a membrane-permeable fluorescence marker. The system has been validated at the laboratory scale using a wide range of water matrices, then installed and validated in different facilities with satisfactory results. Conclusion The MICROALARM system is designed to be portable, thus suitable for on-site applications. It will be a low-cost solution for rapid microbiological analysis. The system will avoid water sampling and transport to the laboratory while enabling on-site quantification of the total bacteria in a reduced timeframe for early decision-making.

Determination of Escherichia coli in urine using a low-cost foil-based microfluidic device

We developed a simple low-cost cultivation-based microfluidic device from office-laminator foil and Parafilm for the determination of specific microorganisms in water samples. The main goal was to obtain a device that would be portable and cheap compared to common laboratory techniques testing microorganisms. This device needs only 10µL of a sample and can be easily used in terrain by a non-specialist. Moreover, we dealt with some technical aspects of the device fabrication such as low-cost lamination techniques and the use of different cultivation media.

"Nanofiltration" Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples.

Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

Microarrays/DNA Chips for the Detection of Waterborne Pathogens.

DNA microarrays are useful for the simultaneous detection of microorganisms in water samples. Specific probes targeting waterborne pathogens are selected with bioinformatics tools, synthesized and spotted onto a DNA array. Here, the construction of a DNA chip for waterborne pathogen detection is described, including the processes of probe in silico selection, synthesis, validation, and data analysis.

Safety assessment of greenhouse hydroponic tomatoes irrigated with reclaimed and surface water

The impact of reclaimed and surface water on the microbiological safety of hydroponic tomatoes was assessed. Greenhouse tomatoes were irrigated with reclaimed and surface water and grown on two hydroponic substrates (coconut fiber and rock wool). Water samples (n=208) were taken from irrigation water, with and without the addition of fertilizers and drainage water, and hydroponic tomatoes (n=72). Samples were analyzed for indicator microorganisms, generic Escherichia coli and Listeria spp., and pathogenic bacteria such as Salmonella spp. and Shiga-toxigenic E. coli (STEC), using multiplex real-time PCR (RT-PCR) after enrichment. The correlation between climatological parameters such as temperature and the levels of microorganisms in water samples was also determined. In irrigation water, generic E. coli counts were higher in reclaimed than in surface water whereas Listeria spp. numbers increased after adding the fertilizers in both water sources. In drainage water, no clear differences in E. coli and Listeria numbers were observed between reclaimed and surface water. No positive samples for STEC were found in irrigation water. Presumptive positives for Salmonella spp. were found in 7.7% of the water samples and 62.5% of these samples were reclaimed water. Salmonella-positive samples by RT-PCR could not be confirmed by conventional methods. Higher concentrations of E. coli were associated with Salmonella-presumptive positive samples. Climatological parameters, such as temperature, were not correlated with the E. coli and Listeria spp. counts. Tomato samples were negative for bacterial pathogens, while generic E. coli and Listeria spp. counts were below the detection limit. The prevalence of presumptive Salmonella spp. found in irrigation water (reclaimed and surface water) was high, which might present a risk of contamination. The absence of pathogens on greenhouse hydroponic tomatoes indicates that good agricultural practices (GAP) were in place, avoiding the microbial contamination of the fruit.

English

In most rural communities in Nigeria, access to potable water is still a challenge. Water quality monitoring was conducted on six (6) surface water catchments in Obokun rural communities in South-Western Nigeria. Parameters were determined using internationally accepted procedures. Among the examined water chemical parameters, only NO3 (50.0 – 154 mg/l) and Mg (20.0 – 110 mg/l) exceeded the WHO and the Nigerian Standard for Drinking Water Quality (NSDWQ) recommended thresholds for potable water. All the surface water samples contained total heterotrophic bacteria (THB) (1100 – 5900 cfu/ml) and total coliform (9.00 – 78.0 cfu/100 ml) above tolerant level. Total heterotrophic fungi (THF) were found in 1.00 – 7.00 cfu/ml density range. All the samples (100%) contained thermotolerant coliform (4.0 – 11.0 cfu/100m l), Escherichia coli (4.00 – 7.00 cfu/100 ml), faecal streptococci (1.00 – 5.00 cfu/ml) and Salmonella (1.00 – 8.00 cfu/100 ml) while 67% contained Shigella (1.00 - 6.00 cfu/100 ml). Presence of pathogenic microorganisms in water samples is indicative of faecal contamination. Multidrug resistance ofPseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, E. coli andCorynebacterium ulcerans showed that these organisms could pose a serious health threat to the users of the water from these rivers. The qualities of surface water samples used for this study were therefore not suitable for human consumption without adequate treatment. However, most rural community people still rely on surface water for drinking and other domestic use. Identification of cost-effective local water treatment techniques and implementation of WHO Water Safety Plan (WSP) will improve water quality and minimize risks to human health. Key words: surface water, rural water, quality surveillance, microorganisms, antibiotic sensitivity.

CONTROLE DE QUALIDADE ANALÍTICA DOS MÉTODOS UTILIZADOS PARA A DETECÇÃO DE PROTOZOÁRIOS PATOGÊNICOS EM AMOSTRAS DE ÁGUA

RESUMO As espécies de protozoários patogênicos de veiculação hídrica Giardia spp. e Cryptosporidium spp. foram responsáveis por cerca 90% dos surtos de gastroenterite ocorridos nos últimos 25 anos, em vários países. Critérios de avaliação das etapas referentes à detecção destes agentes em amostras de água, tais como: precisão inicial, inoculação nas amostras em água bruta e, diagnóstico e localização de erros estão abordados neste trabalho. Estes critérios devem ser correntemente aplicados e constantemente avaliados pelos laboratórios, a fim de assegurar a confiabilidade dos resultados obtidos durante um monitoramento e, assim, fornecer subsídios para uma avaliação do risco de surtos.

Design and preliminary results of a DNA chip for the detection of microorganisms in water samples

AbstractWaterborne pathogens are responsible for several diseases, either due to the consumption of contaminated drinking water or due to the contact with polluted recreational waters. There is an increasing awareness that emergent and viral pathogens should also be monitored for determining water quality. Conventional detection methodologies present several shortcomings, such as reliance in indicator species, low throughput and increasing resources as more species are to be detected. DNA chips have the potential to serve as surveillance systems for the simultaneous detection of pathogens, overcoming these limitations. In the present study, a rapid method for the detection of multiple waterborne pathogens (bacteria and viruses) was developed, using a DNA chip (AQUACHIP®). Species and group specific probes were implemented on a DNA chip, both for mandatory and non‐mandatory microorganisms. Considerations regarding the AQUACHIP® design (probe layout, replicates and dilutions), DNA labelling and amplification, and preliminary results of the application of the chip for the detection of E. coli DNA are presented (© 2010 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

The study of diagnostic techniques for the sources of Escherichia coli at Ta-An Beach

Ta-an Beach in Taichung County, central Taiwan, was found to have exceeded 1,000 CFU/100 ml, 51% of the total monitoring records. It is difficult to identify the contamination source using traditional Escherichia coli and Enterococci analysis. Therefore, a more advanced method known as molecular biotechnology is adopted in this study to diagnose the sources of E. coli at Ta-An Beach. After comparing several different groups of micro-organisms in water samples, we know that there are E. coli and Bacillus. This shows that the beach water quality is indeed affected by contamination from land drainage, and the numbers of E. coli and non-E. coli coliform in land drainage is far greater than that normally found at the beach. The analytical methods and techniques used in this study were not significantly different from the results detected using standard data analysis. The proposed method has high stability and reliability, providing ways to track and identify future of contamination.

Evaluation of a Filtration/Dispersion Method for Enumeration of Particle‐associated Escherichia coli

The transport processes of microorganisms in storm-generated flows have not been clearly elucidated, limiting the ability of computational models to effectively design and evaluate watershed remediation plans. Although several studies have identified association with particulates as a critical factor in predicting microbial transport and fate, no generally accepted method exists for the identification of the planktonic and particle-associated fractions of microorganisms in water samples. In this study, a filtration/dispersion method proposed for quantification of these fractions was verified using laboratory-composed samples of bovine Escherichia coli and sterile topsoil. A statistical experimental design allowed quantification of potential sources of experimental error (e.g., filter retention, die-off), although no significant sources of methodological error were identified. On average, 78% of E. coli cells were particle associated after 1 h of contact time. Further application of the method was illustrated by an isotherm experiment examining the association of a bovine strain of E. coli with sterile topsoil. Further examination of this method in laboratory or field-based studies of microbial partitioning between the planktonic and particulate phases in surface runoff appears justified.

下水処理場における病原ウイルスの低減効果の解明

The occurrence of pathogenic viruses and indicator microorganisms in water samples from a wastewater treatment plant in Japan was investigated monthly from July 2003 to June 2004. Forty-eight samples of raw sewage, treated sewage before chlorination, effluent after chlorination, and reclaimed water after advanced wastewater treatment using sand filtration and ozonation were subjected to a virus concentration method using an HA electronegative membrane, followed by virus detection using a TaqMan PCR method. Noroviruses of genogroups I and II were detected in all 12 raw sewage samples, showing much higher concentrations in winter, an epidemic season. Corresponding to the occurrence in raw sewage, the concentrations of noroviruses in treated sewage and effluent also increased in winter. The concentrations of enteroviruses and adenoviruses in the tested samples were relatively constant compared with those of noroviruses. Noroviruses and adenoviruses were still detected even after advanced wastewater treatment, but the concentrations of these viruses were much lower than those in the effluent samples. Viruses were removed by wastewater treatment as effectively as indicator microorganisms (total coliforms, Escherichia coli, and F-specific phages), suggesting that sewerage systems can contribute to reducing the load of pathogenic viruses discharged into aquatic environments.

A microbiological study of an underground gas storage in the process of gas injection

The numbers of microorganisms belonging to ecologically significant groups and the rates of terminal microbial processes of sulfate reduction and methanogenesis were determined in the liquid phase of an underground gas storage (UGS) in the period of gas extraction. The total number of microorganisms in water samples from the operation and injection wells reached 2.1 x 10(6) cells/ml. Aerobic organotrophs (including hydrocarbon- and oil-oxidizing ones) and various anaerobic microorganisms (fermenting bacteria, methanogens, acetogens, sulfate-, nitrate-, and iron-reducing bacteria) were constituent parts of the community. The radioisotopic method showed that, in all the UGS units, the terminal stages of organic matter decomposition included sulfate reduction and methanogenesis, with the maximal rate of these processes recorded in the aqueous phase of above-ground technological equipment which the gas enters from the operation wells. A comparative analysis by these parameters of different anaerobic ecotopes, including natural hydrocarbon fields, allows us to assess the rate of these processes in the UGS as high throughout the annual cycle of its operation. The data obtained indicate the existence in the UGS of a bacterial community that is unique in its diversity and metabolic capacities and able to make a certain contribution to the geochemistry of organic and inorganic compounds in the natural and technogenic ecosystem of the UGS and thus influence the industrial gas composition.

Effects of large-scale poultry farms on aquatic microbial communities: A molecular investigation

The effects of large-scale poultry production operations on water quality and human health are largely unknown. Poultry litter is frequently applied as fertilizer to agricultural lands adjacent to large poultry farms. Run-off from the land introduces a variety of stressors into the surface waters including nutrients, antimicrobials and pathogenic bacteria. The Delaware, Maryland and Virginia (Delmarva) Peninsula has the highest concentration of broiler chickens per farm acre in the United States and provides an ideal location for studying the effects of stressors from poultry farms. We investigated potential effects by characterizing shifts in the structure of aquatic bacterial communities. DNA was isolated from microorganisms in water samples from streams and rivers at varying distances from, or having different frequencies of, litter applications. Fingerprints of 16S rDNA amplicons from bacteria in water samples collected during late summer 2001 to late spring 2002 were produced by denaturing gradient gel electrophoresis (DGGE). A statistical analysis of multiple fingerprints from each sampling location demonstrated that each site harboured a bacterial community significantly different from the communities at other sites. Similarly, the bacterial communities from each sampling time differed significantly from communities at other sampling times. Most importantly, a competitive, library-based analysis showed time of sampling (month) had a greater effect on community structure than did location.

Rapid Parallel Detection of Hygienically Relevant Microorganisms in Water Samples by PCR and Specific Hybridization in Microtiter Plates

A molecular biological test protocol for the parallel detection of enterococci and Pseudomonas aeruginosa in drinking water was developed. Amplicons labelled with digoxigenin during PCR were hybridized to specific 23S rDNA targeted oligonucleotide probes immobilized in microtiter plates. Detection was performed by addition of anti-digoxigenin-peroxidase-conjugate and chromogenic substrate. Specificity of the probes was evaluated by using pure cultures. First evaluation data with natural water samples in comparison to conventional microbiological analysis according to the German Drinking Water Regulation showed good agreement. Its feasible and rapid performance should be advantageous for use in routine drinking water quality control. Further comparative evaluation studies need to be undertaken to determine the true applicability for routine testing of water samples.

Potential usefulness of bacteriophages that infect Bacteroides fragilis as model organisms for monitoring virus removal in drinking water treatment plants

The presence of bacteriophages at different stages in three drinking water treatment plants was evaluated to study the usefulness of phages as model organisms for assessing the efficiency of the processes. The bacteriophages tested were somatic coliphages, F-specific coliphages, and phages infecting Bacteroides fragilis. The presence of enteroviruses and currently used bacterial indicators was also determined. Most bacteriophages were removed during the prechlorination-flocculation-sedimentation step. In these particular treatment plants, which include prechlorination, phages were, in general, more resistant to the treatment processes than present bacterial indicators, with the exception, in some cases, of clostridia. Bacteriophages infecting B. fragilis were found to be more resistant to water treatment than either somatic or F-specific coliphages or even clostridia. Enteric viruses were found only in untreated water in low numbers, and consequently, the efficiency of the plants in the removal of viruses could not be evaluated with precision. The numbers and frequencies of detection of the various microorganisms in water samples taken in the distribution network served by the three plants confirm the results found in the finished water at the plants.